RUTLAND — On the day Melissa Barratt was killed Doug Radcliffe received a call, he said, from Frank Caraballo demanding money to cover thousands of dollars worth of drugs Caraballo suspected she had a hand in stealing from him.

Radcliffe testified Thursday in Caraballo’s trial in U.S. District Court in Rutland, where he stands accused of killing Barratt in July 2011.

At the time, Radcliffe testified, he was a heroin and crack cocaine addict living in Brattleboro, where he said he bought drugs from Caraballo to use and to sell to support his habit.

The 31-year-old Radcliffe said it was a business arrangement that worked for a while. But eventually he became deeply indebted to the Holyoke, Mass., man who fronted him some drugs on July 27, 2011, with orders to make some money.

He told the court he was surprised when Caraballo called him the next morning demanding that he pay all of the $1,800 he owed.

“He said he needed all the money I owed him, but I hadn’t had a chance to sell the drugs he gave me the night before,” Radcliffe said.

When he asked what the hurry was, he said, Caraballo told him that someone stole his safe full of $10,000 worth of heroin, cocaine and crack cocaine.

“He said he thought it was one of two people,” Radcliffe testified. “I said, ‘Let me guess, one of them is Melissa Barratt,’ and he said, ‘Yes.’”

Radcliffe added, “He told me that she had called him away that morning for a booty call and when he came back the safe was gone. He thought she called him away from the hotel room so someone else could get in there and steal it.”

When Radcliffe said he would have struck the Brattleboro woman if she had stole from him, Caraballo allegedly responded: “No, (I’m) so calm it’s scary.”

At some point during multiple discussions on the morning of July 28, 2011, Radcliffe said, Caraballo asked him an unusual question.

“He said he was about to make some noise and he didn’t know where to do it,” Radcliffe said.

Federal prosecutors have argued this week that it was hours after that phone call that Caraballo walked Barratt into a wooded area off East West Road in Dummerston and killed her with a single gunshot to the back of the head.

Radcliffe was one of more than a half-dozen witnesses to take the stand on the fourth day of Caraballo’s homicide and drug distribution trial.

Federal prosecutors spent much of the day laying evidentiary foundations by calling a mobile phone company manager to the stand to testify about Caraballo’s phone records; hearing forensic evidence that showed the heroin, crack cocaine and powder cocaine bought from Caraballo’s alleged drug ring was real; and analyzing motel receipts at places where he stayed.

They also called a handful of people who testified about their involvement in Caraballo’s alleged drug- and gun-trade activities.

Jacqueline Derby, 21, of Newfane, told the jury that she stole a Glock handgun — of the same caliber as the one used to kill Barratt — from a home she was staying at in Bellows Falls.

She said she traded the gun for a small amount of crack cocaine and to erase a debt she owed.

On Wednesday jurors had heard from Putney resident Thomas Parrott, who said he received the gun that Derby stole and traded it to Caraballo for crack cocaine roughly two weeks before Barratt was killed.

Toni Lynn Fontaine, 26, of Brownsville, told the jury Thursday that when she was living in Brattleboro in 2011 she traded a stolen Desert Eagle .357-caliber handgun to Caraballo to erase a drug debt she owed him.

Defense attorneys Mark Kaplan and Natasha Sen attacked the credibility of Fontaine and Radcliffe, who both accepted plea deals from federal prosecutors for sentencing consideration on drug-distribution charges that could send them to jail for up to 20 years.

Kaplan also questioned Radcliffe repeatedly about his history of cooperating with police to have criminal charges reduced or eliminated.

“You figure you’ll always get out of it and the reason is, you shift the blame to somebody else,” Kaplan said. “You’ve done that over and over and over.”